1. Field of the Invention
The present invention relates to a power supply control apparatus of an electric load in which plural switching elements are provided in a power supply circuit with respect to an electric load, and even though any switching element among the plural switching elements is short-circuited, a load current can be cut off by the other switching element, and particularly, to a power supply control apparatus of an electric load improved to be able to identify and store various abnormality states of a load wiring by a small number of abnormality monitoring signals.
2. Description of the Background Art
For example, in an on-vehicle electric load, when plural power supply switching elements are connected between a direct current power source that is an on-vehicle battery and each of plural on-vehicle electric loads, and when any power supply switching element is in a short circuit abnormality state, overall power supply is stopped by a common power source relay or a common power supply cutoff element, or the power supply is individually stopped by plural power supply cutoff elements that are serially connected to respective electric loads. For example, according to FIG. 1 in Patent Document 1, a power supply cutoff element 15 and a driver element 14a are serially connected, and even though the driver element 14a is in a short circuit abnormality state, it is possible to stop power supply to a coil load 13 by the power supply cutoff element 15, and to identify and detect an open fault or a short circuit fault of the coil load 13, an open fault or a short circuit fault of the driver element 14a using a voltage detecting circuit 14b. Further, according to Patent Document 2, switch elements 33 and 34 are connected on an upstream side of an injector 13 that is an electric load, a switch element 36 is connected on a downstream side thereof, in which a current or voltage of each switch element is monitored by a diagnosing section 42, and the diagnosis result is serially transmitted to a control unit 39.
[Patent Document 1] JP-A-2003-047148
[Patent Document 2] JP-A-2004-124890